I'm not sure I understand the method.

Is it correct that the study looked at the effect of a single (large) dose of ketones, rather than ongoing consumption?

As I understand it, dosage was 0.395g per kilo of body weight (so about 27g for 70kg subject), and that was it - with measurements of brain activity before and after.

No indication of duration of effect?

I Googled and have found a product on Amazon, which is asking about 30 USD for that dose, which would make daily 900 USD a month (!)